Avalanche Forecast

Weakening low pressure systems will pass near Cape Flattery on Sunday and near Astoria on Monday. This will generally cause a trend of increasing alpine winds and increasing snow especially in the south Cascades by Monday. Temperatures should not change greatly through Monday. Expect about 5-10 inches of snow along the Cascade east slopes on Sunday and Monday with the most in the south part.

This will cause the avalanche danger along the Cascade east slopes to go up another notch on Monday especially in the south part.

The size and extent of wind slab should generally increase on Monday especially in the southeast zone. Watch for firmer wind transported snow on potential lee slopes. Significant winds lately and on Monday will have been mostly south to southwest so north to southeast aspects will be indicated but keep an eye on all aspects.

The size and extent of storm slab should also generally increase on Monday especially in the southeast zone. Storm slab is most likely in areas that receive more than a few inches of rapidly accumulating snowfall.

Loose wet avalanches will not be indicated as an avalanche problem but watch for loose wet surface snow if you find yourself on solar slopes during cloud or sun breaks.

Weather and Snowpack

Hopefully the last atmospheric river of the season arrived on Valentines Day 2/14.

In the Northeast zone the NWAC station at Washington Pass received about 10-14 inches of moist snow over the melt-freeze crust from the fair weather by Thursday morning. Reports also indicated a thin surface freezing-rain crust to near treeline.

In the Central East and Southeast zones light to moderate snow with warmer temperatures and some high snow levels occurred with localized freezing rain along the lower east slopes. Then above freezing temperatures occurred during precipitation with light rain likely up to about 5-6000 feet in the Central East and up to about 7000 feet in the Southeast.

A short period of fair weather on Friday 2/17 caused another surface crust in many areas.

Some snow was seen with light winds on Saturday. NWAC stations along the Cascade east slopes had up to about 2 inches ending Sunday morning.

Temperatures haven't changed much on Friday to Sunday.

Recent Observations

North

NWAC observer Jeff Ward was out Thursday, 2/16 and reported the recent about 10 inches of  moist storm snow was being transported and building wind slabs through the day. There was evidence of a few natural wind slab releases and a natural storm slab was noted releasing sometime Thursday.

More NCMG reports on Friday in the Hairpin Valley near Washington Pass indicated shears at the interface of the storm snow a prior melt-freeze crust, down about 14 inches. But ski test gave no results and no avalanches were seen. Snowmobiles were high marking also with no triggered slides, also indicating good stabilizing of recent storm snow.

The NCMG were out again in the Hairpin Valley on Saturday and found slab structures lacking in the recent storm snow with ski tests even on steep convex rolls not giving results.

The NCMG were out yet again near Washington Pass on Sunday and reported that ski tests on steep features gave no results and that wind slab was generallly unreactive. A size 2.5 likely cornice triggered 1 m x 200 m crown was seen on a north aspect at 7200 feet that probably released about 2/15.

Central

On Thursday 2/16, warm temperatures had reached the lower east slopes and numerous wet snow avalanches had released in Tumwater Canyon.

Reports from the Mission Ridge pro-patrol Friday 2/17 indicated that the previous wet snowpack had locked up and formed a strong surface crust in most terrain with little to no new snow above.

South

No recent observations.